NLO Crystal Research Articles

Crystal property and spectroscopic investigation on electro-optic and physico-chemical properties of NLO crystal; 3-(3,4-Dihydroxyphenyl)-L-Alanine

In this attempt, in order to obtain high-quality NLO crystal, organic compound; 3-(3,4-Dihydroxyphenyl)-L-Alanine crystal was fabricated. The organic-composite crystal was characterized by crystallographic and spectroscopic tools. The NLO supported parameters like crystal lattice (orthorhombic) and space group (P212121) examined and validated by XRD examination. The SHG test was carried out and SHG efficiency was calculated that1.29 and 1.35 times greater than solid KDP crystal. The laser damage threshold energy density was determined to be 14.51 GW/cm2. By the application of mulliken charge assignment, multiple dielectric cavities were found in crystal material which is able to process the high degree of birefringence gradient. The oscillating chemical potential movement was observed by examining chemical shift, among the core carbons of hexagonal ring and bridge carbons of chain. The chemical softness insists the binding viability of further ligand groups. The π and δ-conjugated interactive complex orbitals recognized on molecular site and participation in optical active mechanism was identified. UV-Visible transmission characteristics of crystal were studied and UV-Visible absorption on degenerate energy states was noted and its band gap energy was estimated. The CT complex of the present case was acknowledged to be COOH group and it causing crystal properties of current organic composite. The hyperactive polarizability was determined as 1775.05 × 10−33 esu and it was found to be five times greater than thiourea. The depletion energy between highly electrophilic zones and protonic zones was estimated to be ±5.241 e 2 causing permanent dielectric characteristics for the title organic composite. The non-superposable on the molecular mirror image was displayed and thereby optical ability was validated.

Studies on third order nonlinear optical properties of Nickel Boro Phthalate NLO crystal

Single crystals of Nickel Boro Phthalate (NBP) are grown by the slow evaporation technique. The crystals are subjected to Single crystal x-ray diffraction to analyse the crystal lattice parameters, and the crystal structure is found to be triclinic. The presence of functional groups has been estimated qualitatively from the Fourier transform infrared spectroscopy and elemental analysis is done using the Energy dispersive x-ray spectral study. The UV-visible spectral studies indicate a broad window of transparency in the entire visible and infrared region and the fundamental frequency is determined to be 285 nm. Optical properties such as the dielectric constant, polarizability, susceptibility, optical and electrical conductivity are presented graphically. Third-order nonlinear parameters are evaluated by the Z scan technique using continuous wave 532 nm diode- pumped Nd:YAG laser. Closed aperture mode indicates the self-defocusing nature and negative nonlinearity of the crystal. Open aperture mode reveals the saturation absorption within the crystal. The nonlinear optical parameters such as nonlinear refractive index n2, nonlinear absorption coefficient β and nonlinear susceptibility χ(3) are also determined.

Growth, characterization and influence of gamma irradiation on strontium chloride doped urea: An NLO crystal

Single crystal of strontium chloride doped urea (SCU) was grown by slow evaporation technique at room temperature. The single crystal X-ray diffraction study revealed that SCU belongs to the tetragonal system. Incorporation of strontium was confirmed by powder XRD, EDAX and ICP-OES studies. The presence of strontium enhanced the thermal stability of urea from 130 °C to 165 °C. The SHG efficiency measured by Kurtz-Perry powder technique is found to be 0.52 and 0.84 times that of urea and KDP respectively. Further, the gamma radiation effect was studied on powder XRD, energy gap and SHG efficiency and is observed that these parameters are decreased upon irradiation.

Structure–Property Correlation Studies of Potassium 4,4′-Bis(dinitromethyl)-3,3′-azofurazanate: A Noncentrosymmetric Primary Explosive

The knowledge of mechanical, vibrational, electronic properties, and origin of polarizability of a noncentrosymmetric explosive materials plays a crucial role in understanding the phase transition mechanism and stand-off detection of high energy material (HEM) residues on the surfaces and interfaces. In the present study, we have explored the role of crystal structure and chemical composition in predicting the structural, dynamical, electronic, and optical properties of two newly synthesized noncentrosymmetric green primary explosives, potassium 4,4′-bis(dinitromethyl)-3,3′-azofurazanate (K2BDAF) and potassium 1,1′-dinitramino-5,5′-bistetrazolate (K2DNABT), using density functional theory simulations. The calculated structural and mechanical properties suggest that K2BDAF and K2DNABT are mechanically stable and possess lower bulk modulus values [K2BDAF (18.91 GPa) < K2DNABT (22.4 GPa)] than toxic lead azide Pb(N3)2 (26 GPa). The Born effective charge (BEC) and vibrational, thermodynamic, and phonon dispersion studies reveals that both crystals are dynamically stable and that K2BDAF is found to be more stable, more polarizable, and easily detectable than K2DNABT. The TB-mBJ electronic band structure study reveals that K2BDAF is an indirect band gap (along R → V high symmetry points) material with a gap of 2.37 eV < K2DNABT (3.57 eV, direct). The density of states and charge density plots show that both crystals possess mixed covalent and ionic bonding nature, and these results are consistent with BEC analysis. The nitrogen, oxygen and carbon p states are found to be dominant near the Fermi level in the valence band. From the optical properties study, it is found that the studied explosive materials have the lowest dielectric constant compared with the well-known 4-N,N-dimethylamino-4-N-methylstilbazolium tosylate (DAST) crystal, i.e., K2DNABT (2.68) < K2BDAF (2.91) < DAST (5.2), and show birefringence similar to (K2BDAF static value, 0.32; at 532 nm, 0.58), (K2DNABT static value, 0.25; at 532 nm, 0.27) that of DAST (0.39, 0.55, 0.64) and 4-N,N-dimethylamino-4′-N′-methylstilbazolium 2,4,6-trimethylbenzenesulfonate (DSTMS) (0.45, 0.63) NLO crystals. For both the studied explosives, the absorption is found to be strong in the [010] direction and follows the relation α(K2BDAF) < α(K2DNABT). The analysis of differences in BEC reveals that from K2DNABT to K2BDAF, the positive contribution of atoms to total birefringence increases as follows: K1 (0.09559), O1 (0.69236), O2 (0.77962), N1 (1.41018), N2 (0.92394), N3 (0.27415), N4 (0.74264), and N5 (0.84502). The negative contribution from C1 is increased by −1.29582. Over all, our results are in agreement with the experimentally reported sensitivity trend, and the reasons behind the sensitivity differences of K2DNABT and K2BDAF are explored.

Growth, electrical and optical studies, and terahertz wave generation of organic NLO crystals: DSTMS

The raw material of 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium 2,4,6-trimethylbenzenesulfonate (DSTMS) is synthesized by a condensation method under the catalysis of piperidine.

Synthesis, physicochemical and quantum chemical studies on a new organic NLO crystal: Cinnamoylproline

Cinnamoylproline was synthesized and the crystal was grown from solution by the slow evaporation method. The crystal belongs to the trigonal crystal system with non-centrosymmetric space group P31. The calculated geometry and experimental geometry from single crystal X-ray data were compared. Intermolecular interactions were studied using Hirshfeld surface analysis and its real space functions were calculated using Atoms In Molecules (AIM) and its isosurfaces were visualized using Non-covalent interaction analysis. Optical transparency of the crystal was analyzed by UV–Vis analysis and it was found that the crystal has good optical transparency in the visible range and the lower cut-off wavelength was found to be 326 nm. In the photoluminescence spectrum, a broad emission peak at 369 nm was observed. The functional groups were analyzed using FTIR techniques and the vibrational frequencies from experimental and theoretical values were compared. It was inferred from the TG-DTA studies that the crystal was thermally stable up to 375 °C. Kurtz-Perry powder SHG analysis was also carried out with KDP as a reference. It showed that the crystal has 1.08 times greater efficiency than KDP. The first hyperpolarizability tensor of the molecule was calculated theoretically and theoretical second order susceptibility was obtained and compared with the experimental susceptibility.

Synthesis, crystal structures and nonlinear optical properties of polymorphism: α- and β-RbHgI3·H2O

New noncentrosymmetric polymorphs, namely, α- and β-RbHgI3·H2O, have been synthesized by conventional solution reaction. The two titled compounds crystallize in the monoclinic space groups Cc (no. 9) and Pc (no. 7), respectively. In their crystal structures, [HgI4] tetrahedrons connect with each other via sharing corners into one-dimensional (1-D) [HgI3] chains, and then all the 1-D chains connect with [Rb(H2O)]+ complexes to form the three-dimensional (3-D) frameworks. The consistent packing style results in a strong macroscopic nonlinear optical effect due to the superimposition of the microscopic second-order susceptibilities of [HgI4] tetrahedra. Powder second-harmonic generation (SHG) measurements show that both α- and β-RbHgI3·H2O are phase-matchable (type I), and the measured SHG coefficients are about 15.0 and 14.0 times that of KH2PO4 (KDP). Both the compounds exhibit wide transparency from near UV to mid and far-infrared region, suggesting that α- and β-RbHgI3·H2O are potential infrared NLO crystals. Band structure and optical property were also calculated by DFT methods.

Influence of Zinc and Ammonium Compounds on the Growth and Characterisation of L Alanine NLO Crystals

Influence of Zinc and Ammonium Compounds on the Growth and Characterisation of L Alanine NLO Crystals

Combined experimental and theoretical investigation of l-Histidinium trichloro zinc: a novel nonlinear optical material

The l-Histidine based first metal organic NLO crystal, l-Histidinium trichloro zinc (HZC) is successfully grown from slow evaporation method. The experimental and theoretical investigations performed exploitation in the field of nonlinear optics. Single crystal X-ray diffraction study confirms the crystal belongs to orthorhombic system with the space group P212121. The crystal has wide optical transmission window from 302 to 1000 nm. TGA/DSC shows the compound has high melting point (200 °C) away its family. Optimized molecular geometry, molecular orbital analysis and hyperpolarizability calculations are carried out using density functional theory. The energy gap of HOMO–LUMO expresses the intramolecular charge transfers in the molecule. Hirshfeld surface analysis exposes that H‧‧‧Cl and Cl‧‧‧H are the strongest hydrogen bond interactions. Theoretical calculation implies that first-order polarizability is 8 times greater than urea. The results revealed that the HZC may useful for optoelectronic applications.

Crystal engineering, structural and optical properties of 2-aminopyridinium diphenylacetate diphenylacetic acid crystal

Organic crystal of 2-aminopyridinium diphenylacetate diphenylaetic acid with dimensions 22 × 13 × 11 mm3 was grown by slow cooling technique. The structural confirmation has been done using single crystal X-ray diffraction study. The title compound crystallizes in the monoclinic crystal system with noncentrosymmetric space group P21. The C-H-O, N-H-O type of packing for the title compound has been reported. Optical transmittance shows a wide transparency in the visible region with lower cutoff wavelength at 349 nm. The four independent tensor coefficients of dielectric permittivity were found to be ε11 = 12.16, ε22 = 10.68, ε33 = 11.90 and ε13 = −4.24 from the dielectric measurements. The thermal stability of the 2APD compound was found to be 128˚C assessed by TG-DTA analyses. The particle size SHG of the 2APD reveals that it is a phase-matchable NLO crystal.

Prediction and Characterization of NaGaS2, A High Thermal Conductivity Mid-Infrared Nonlinear Optical Material for High-Power Laser Frequency Conversion

Infrared nonlinear optical (IR NLO) crystals are the major materials to widen the output range of solid-state lasers to mid- or far-infrared regions. The IR NLO crystals used in the middle IR region are still inadequate for high-power laser applications because of deleterious thermal effects (lensing and expansion), low laser-induced damage threshold, and two-photon absorption. Herein, the unbiased global minimum search method was used for the first time to search for IR NLO optical materials and ultimately found a new IR NLO material NaGaS2. It meets the stringent demands for IR NLO materials pumped by high-power laser with the highest thermal conductivity among common IR NLO materials able to avoid two-photon absorption, a classic nonlinear coefficient, and wide infrared transparency.

SnI4 ⋅(S8 )2 : A Novel Adduct-Type Infrared Second-Order Nonlinear Optical Crystal.

A simple adduct from tin tetraiodide SnI4 and octasulfur S8 , SnI4 ⋅(S8 )2 (1), is obtained employing a facile reaction. The combination of Sn4+ ions with d10 electron configuration, acentric SnI4 tetrahedra, and lone-pair effects of S8 , makes 1 a phase-matchable infrared NLO crystal with a moderate second-harmonic generation (SHG) response and a very high laser-induced damage threshold (LIDT), which is well confirmed by the DFT calculations.

SnI4⋅(S8)2: A Novel Adduct‐Type Infrared Second‐Order Nonlinear Optical Crystal

AbstractA simple adduct from tin tetraiodide SnI4 and octasulfur S8, SnI4⋅(S8)2 (1), is obtained employing a facile reaction. The combination of Sn4+ ions with d10 electron configuration, acentric SnI4 tetrahedra, and lone‐pair effects of S8, makes 1 a phase‐matchable infrared NLO crystal with a moderate second‐harmonic generation (SHG) response and a very high laser‐induced damage threshold (LIDT), which is well confirmed by the DFT calculations.

Selective enhancement of second and third-order nonlinear optical properties of newly synthesised trisglycine epsomite single crystal

An exceedingly high-quality second and third-order nonlinear optical (TONLO) single crystal trisglycine epsomite (TGE) has been grown productively using aqueous solution by conventional solution growth method. Single crystal XRD confirms the distortion of crystal structure from orthorhombic to triclinic with space group. CHN analysis authenticates the occurrence of carbon, hydrogen and nitrogen in the grown crystal. FTIR studies substantiate the existence of functional groups. The optical transmission studies proves the transparency of the sample in the entire visible region and band gap was determined using Tauc’s plot. The output intensity of SHG was verified by Kurtz and Perry powder technique and it was found to be 0.792 times greater than that of KDP. TONLO properties such as nonlinear refraction (NLR), nonlinear absorption (NLA), third-order susceptibility (χ3) and hyperpolarizability (γ) were determined with high accuracy using effectively attributes to self-defocusing effect also with high third-order susceptibility comparing to other NLO crystals. SEM analysis reveals the surface morphology of the grown crystal.

Hydrothermal single crystal growth and second harmonic generation of Li2SiO3, Li2GeO3 and Li2Si2O5

The growth of large high quality single crystals of three lithium silicates and germanates Li2SiO3, Li2SiO5, and Li2GeO3 is described. The crystals are all grown using hydrothermal fluids at 650 °C and 1 kbar using simple oxide feedstock and 3–6 M LiOH serving as both the lithium ion source and mineralizer. The crystals could be grown by spontaneous transport without any specific seeding, and grew between 2 and 10 mm/edge and without evidence of cracking, physical twinning or multiple domain structures. The crystals were characterized by single crystal diffraction, UV–vis spectroscopy and Raman spectroscopy. All the crystals are acentric and polar. Preliminary nonlinear optical properties were investigated using the Kurtz method and indicate that the crystals exhibit Type-1 phase matching ability, and Li2SiO3 demonstrates a significant nonlinear optical conversion efficiency, making it of potential interest as a UV NLO crystal.

Bulk crystal growth and their effective third order nonlinear optical properties of 2-(4-fluorobenzylidene) malononitrile (FBM) single crystal

2-(4-fluorobenzylidene) malononitrile (FBM), an organic third order nonlinear (TONLO) single crystal with the dimensions of 32 × 7 × 11 mm3, has been successfully grown in acetone solution by slow evaporation technique at 35 °C. The crystal system (triclinic), space group (P-1) and crystalline purity of the titular crystal were measured by single crystal and powder X-ray diffraction, respectively. The molecular weight and the multiple functional groups of the FBM material were confirmed through the mass and FT-IR spectral analysis. UV–Vis–NIR spectral study enroles that the FBM crystal exhibits excellent transparency (83%) in the entire visible and near infra-red region with a wide bandgap 2.90 eV. The low dielectric constant (εr) value of FBM crystal is appreciable for microelectronics industry applications. Thermal stability and melting point (130.09 °C) were ascertained by TGA-DSC analysis. The laser-induced surface damage threshold (LDT) value of FBM specimen is found to be 2.14 GW/cm2, it is fairly good compared to other reported NLO crystals. The third - order nonlinear optical character of the FBM crystal was confirmed through the typical single beam Z-scan technique. All these finding authorized that the organic crystal of FBM is favorably suitable for NLO applications.

Praseodymium doped KDP Single Crystal Grown by Different Techniques and its Optical, SHG and Dielectric Studies : A New NLO Crystal

Praseodymium doped KDP Single Crystal Grown by Different Techniques and its Optical, SHG and Dielectric Studies : A New NLO Crystal

Structural, optical, thermal and theoretical investigations on high efficiency NLO crystal: 4-Nitrobenzonitrile

Crystals of 4-Nitrobenzonitrile have been grown from the solution growth procedure. Various characterization techniques have been adopted like powder XRD, FT-IR, UV–vis, photoluminescence and Powder SHG to investigate the crystal further. Powder XRD data reveals that the title compound gets crystallize in to monoclinic system with P21 space group.. Functional groups were recognized and its vibrational behaviour has been studied from FT-IR analysis. Optical transparency of the crystal was tested by using the UV–vis spectrum. Fluorescence spectrum shows the peak at 528 nm. The second harmonic conversion efficiency of the crystal is nearly about 14.5 times greater to KDP and 5.8 times that of urea.

Influence of formic acid on optical and electrical properties of glycine crystal

A remarkable influence of formic acid on various properties of glycine single crystal has been investigated. The formic acid doped glycine crystals were grown by slow evaporation solution growth technique. The structural parameters of pure and doped glycine crystals were determined using single crystal x-ray diffraction technique. The presence of functional groups and the red shift caused by dopants were confirmed by FT-IR and FT-Raman spectroscopy. The UV–visible studies measures optical transparency, wide optical band gap (6.32 eV) and lower cutoff wavelength in glycine formic acid (GLFA) crystals. The Second Harmonic Generation measurement reveals high SHG efficiency in doped crystals compared with other glycine based NLO crystals. Dielectric studies were carried out and it explores low dielectric constant and dielectric loss for pure and doped samples. Ferro electric measurement was done to find the value of Remnant polarization (95.71 µC cm−2) and coercive field (583.71 kV cm−1) which have been enhanced for GLFA crystal.

Studies on Molecular Structure and Vibrational Spectra of NLO Crystal L-Glutamine Oxalate by DFT Method

Objectives: To explicate structural features of L-GLUTAMINE OXALATE (LGO) using vibrational spectroscopic methods and DFT computations. To identify the functional groups and hydrogen bonding interactions of the molecule by recording FTIR and FT-Raman spectra. To confirm NLO activity by performing SHG test. Methods/Statistical Analysis: Crystals were grown by slow evaporation method and characterized by powder X-Ray diffraction method. FTIR, FT-Raman, UV-Vis analysis and second harmonic generation test were predicted. DFT analysis using Gaussian’09 program package were performed to confirm the NLO properties theoretically. Findings: Lowering of HOMO-LUMO energy gap value explains the intramolecular charge-transfer interaction which indicates NLO property. Second Harmonic Generation of the sample shows good nonlinearity of the sample. Application/Improvements: LGO sample shows good NLO Properties and can be used in optical field.